I. Field of the Invention
This invention relates to an improved winding mechanism for tape-like webs, particularly a carbon ribbon, or the like. More particularly, the invention relates to an improved winding mechanism for rolled tapelike webs such as composite label webs, composite tag webs and carbon ribbons, which mechanism avoids the slackening, stretching and meandering that occurs with a tape-like web when it is wound from a feeding section to a winding section of the winding mechanism.
II. Description of the Prior Art
A tape-like web, such as a carbon ribbon, is fed from a feeding section, and usually from a feed reel in that section, to a winding section and usually to a winding take-up reel in the latter section. In a mechanism for preventing a tape-like web from slackening, for example, in a conventional label printing machine, or the like, only the feeding section is provided with a braking device. As the feeding section and the winding section are independently driven, when the winding section is driven intermittently, slackening of the tape-like web is caused by the inertia of a delivery or feed roll in the feeding section, so that a constant braking action in the feeding section cannot be produced. Such intermittent driving occurs with a carbon ribbon, for example when the feeding of the carbon ribbon is abruptly stopped for a short time, during the printing or cutting of the web, by a short stoppage of the intermittent driving by a stepping motor that is installed in the winding section.
The rotation of the rolled tape-like web in the feeding section is subjected to braking action under sliding friction. However, when a rolled tape-like web is moved intermittently, the web is moved forward excessively to some extent toward the winding section due to the inertia of the rolled tape-like web. This causes slackening or meandering of the tape-like web.
Furthermore, in a conventional thermal printer having a thermo-sensitive carbon ribbon, printing strokes sometimes occur in transversely biased side portions on the ribbon, i.e., one-sided printing strokes. In that case, slackening of the carbon ribbon is caused by the elongation or contraction of the carbon ribbon during the feeding, and this results in creasing and meandering of the carbon ribbon.
Furthermore, when a web of labels or tags, that are passed together with the carbon ribbon in layers through printing means, is damaged during the printing step, the carbon ribbon and the web of labels or tags must be set again by turning off a printing head or by separating a platen roller. Because the carbon ribbon is moved for a long time in contact with the printing head, the ribbon is attracted to the parts near the printing head by static electricity, causing slackening of the carbon ribbon. When a proper braking action has not been applied to the carbon ribbon, movement of the ribbon is started while the ribbon is slack and there is consequent meandering of the carbon ribbon. If the carbon ribbon has meandered, it has moved aside, and transverse side portions of the labels or tags cannot be printed.